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Sistem Basis DataPertemuan 2 : Pemodelan Data & Pemilihan Tipe Data
Andronicus Riyono, M.T.
Enterprise Data Model
• The first step in database development, in which the scope and general contents of organizational databases are specified.
• Preliminary Data Model
Entity-Relationship Model Constructs
• Basic Symbols
• Entity
• Attribute
• Relationship
• Relationship degree
• Relationship cardinality
Basic Symbols
Derived Attribute Contoh 1
Derived Attribute Contoh II
Derived Attribute Contoh II
Associative Entity
Relationship degree
Relationship Cardinality
Entity
• Entity: A person, place, object, event, or concept in the user environment about which the organization wishes to maintain data.
• Orang: Pegawai, Mahasiswa, Pasien
• Tempat: Toko, Gudang, Provinsi
• Obyek: Mesin, Gedung, Mobil
• Event: Penjualan, Pendaftaran, Perpanjangan
• Konsep: Matakuliah, Pekerjaan
Entity vs Entity Instance
• Entity type: A collection of entities that share common properties or characteristics.
• Entity instance: A single occurrence of an entity type.
• satu macam entity Pelatihan banyak instances (Pelatihan PHP, Pelatihan Oracle, Pelatihan Web Design, Pelatihan MS Office)
Entity vs Input/Output/User
Entity vsInput/Output/User
Entity = hanya yang perlu dicatat datanya saja
Entity Naming Guidelines
• Kata Benda Tunggal (MAHASISWA, PEGAWAI, MOBIL, EMPLOYEE)
• Spesifik (CUSTOMER or CLIENT)
• Singkat (REGISTRATION vs STUDENT REGISTRATION FOR CLASS)
• Konsisten di seluruh E-R Diagram
Memilih Tipe Data
• Hemat Media Penyimpanan
• Mampu Mewakili Semua Nilai yang Diperlukan
• Menjaga/Memperbaiki Kualitas Data
• Mendukung dan Memudahkan Semua Manipulasi Data yang Diperlukan
MySQL 5 Numeric Data Types
• TINYINT
• SMALLINT
• MEDIUMINT
• INT
• BIGINT
Menyimpan Kode
• Mencatat Teks vs. Tabel Referensi
• Meminimalkan Kesalahan Pengetikan
• Memudahkan Update